U.S. Pat. Nos. 4,734,416 and 5,006,528 disclose aripiprazole, 7-{4-[4-(2,3-dichlorophenyl)-1-piperazinyl]butoxy}-3,4-dihydro-2(1H)-quinolinone or 7-{4-[4-(2,3-dichlorophenyl)-1-piperazinyl]butoxy}-3,4-dihydro carbostyril, as an atypical antipsychotic agent useful in the treatment of schizophrenia, bipolar disease, depression, and other CNS disorders. Aripiprazole has the following chemical structure:

Aripiprazole is sold under the trade name ABILIFY®. It acts as a dopamine D2 partial agonist, serotonin 5-HT1A receptor agonist, and is an antagonist of the serotonin 5-HT2A receptor. ABILIFY® is currently administered orally on a once-a-day dosing schedule as ABILIFY® (aripiprazole) Tablets, ABILIFY DISCMELT® (aripiprazole) Orally Disintegrating Tablets, and ABILIFY® (aripiprazole) Oral Solution. Poor and variable patient compliance with a once-a-day dosing schedule of psychiatric drugs has been reported. Efforts have been made to provide drug dosage forms that may increase the compliance of patients and thereby lower the rate of relapse in the treatment of schizophrenia.
U.S. Pat. Nos. 7,807,680, 8,338,427, and 8,338,428 describe long-acting aripiprazole sterile injectable formulations. Studies on aripiprazole free base injections showed a prolonged pharmacokinetic profile, but there have been reports of moderate to severe tissue irritation following intramuscular (IM) injection and subcutaneous (SC) injection. As such, there exists a need for improved methods of delivering antipsychotics, such as aripiprazole, thereby improving patient compliance and maximizing the pharmacological profile of the active agent.